Neel Temperature: Is Magnetisation Equal to Zero?

[Petar Mali]

One question? Neel temperature is temperature in which magnetisation is equal to zero?

 

[weejee]

It is the temperature in which the staggered magnetization (= a measure on how much nearest neighbors tend to align oppositely) is nonzero. The magnetization is both zero for a paramagnet and an antiferromagnet.

 

[Petar Mali]

Can I say for $$\sigma=0$$, $$T=T_N$$?

 

[weejee]

Can I say for $$\sigma=0$$, $$T=T_N$$?

What do you mean by sigma=0? If you mean that the entropy is zero, I don't think so. It holds when all the local moments are 'fully' aligned(such that two nearest neighbors point in opposite directions). At the Neel temperature, such alignment starts to develop.

 

[Petar Mali]

Sigma iz magnetisation!

 

[weejee]

Aha! The magnetization! :) In zero fields, the magnetization in the paramagnet-antiferromagnet transition should be always zero. It is not a suitable measure to characterize the transition.